Identification of receptor-type protein tyrosine phosphatase μ as a new marker for osteocytes

Osteocytes are the predominant cells in bone, where they form a cellular network and display important functions in bone homeostasis, phosphate metabolism and mechanical transduction. Several proteins strongly expressed by osteocytes are involved in these processes, e.g., sclerostin, DMP-1, PHEX, FGF23 and MEPE, while others are upregulated during differentiation of osteoblasts into osteocytes, e.g., osteocalcin and E11. The receptor-type protein tyrosine phosphatase µ (RPTPμ) has been described to be expressed in cells which display a cellular network, e.g., endothelial and neuronal cells, and is implied in mechanotransduction. In a capillary outgrowth assay using metatarsals derived from RPTPμ-knock-out/LacZ knock-in mice, we observed that the capillary structures grown out of the metatarsals were stained blue, as expected. Surprisingly, cells within the metatarsal bone tissue were positive for LacZ activity as well, indicating that RPTPμ is also expressed by osteocytes. Subsequent histochemical analysis showed that within bone, RPTPμ is expressed exclusively in early-stage osteocytes. Analysis of bone marrow cell cultures revealed that osteocytes are present in the nodules and an enzymatic assay enabled the quantification of the amount of osteocytes. No apparent bone phenotype was observed when tibiae of RPTPμ-knock-out/LacZ knock-in mice were analyzed by μCT at several time points during aging, although a significant reduction in cortical bone was observed in RPTPμ-knock-out/LacZ knock-in mice at 20 weeks. Changes in trabecular bon

iPSC-based modeling of RAG2 severe combined immunodeficiency reveals multiple T cell developmental arrests

RAG2 severe combined immune deficiency (RAG2-SCID) is a lethal disorder caused by the absence of functional T and B cells due to a differentiation block. Here, we generated induced pluripotent stem cells (iPSCs) from a RAG2-SCID patient to study the nature of the T cell developmental blockade. We observed a strongly reduced capacity to differentiate at every investigated stage of T cell development, from early CD7(-)CD5(-) to CD4(+)CD8(+). The impaired differentiation was accompanied by an increase in CD7(-)CD56(+)CD33(+) natural killer (NK) cell-like cells. T cell receptor D rearrangements were completely absent in RAG2SCID cells, whereas the rare T cell receptor B rearrangements were likely the result of illegitimate rearrangements. Repair of RAG2 restored the capacity to induce T cell receptor rearrangements, normalized T cell development, and corrected the NK cell-like phenotype. In conclusion, we succeeded in generating an iPSC-based RAG2-SCID model, which enabled the identification of previously unrecognized disorder-related T cell developmental roadblocks

iPSC-Based Modeling of RAG2 Severe Combined Immunodeficiency Reveals Multiple T Cell Developmental Arrests

RAG2 severe combined immune deficiency (RAG2-SCID) is a lethal disorder caused by the absence of functional T and B cells due to a differentiation block. Here, we generated induced pluripotent stem cells (iPSCs) from a RAG2-SCID patient to study the nature of the T cell developmental blockade. We observed a strongly reduced capacity to differentiate at every investigated stage of T cell development, from early CD7−CD5− to CD4+CD8+. The impaired differentiation was accompanied by an increase in CD7−CD56+CD33+ natural killer (NK) cell-like cells. T cell receptor D rearrangements were completely absent in RAG2SCID cells, whereas the rare T cell receptor B rearrangements were likely the result of illegitimate rearrangements. Repair of RAG2 restored the capacity to induce T cell receptor rearrangements, normalized T cell development, and corrected the NK cell-like phenotype. In conclusion, we succeeded in generating an iPSC-based RAG2-SCID model, which enabled the identification of previously unrecognized disorder-related T cell developmental roadblocks.In this article, Mikkers

Decompressing Stoma as Bridge to Elective Surgery is an Effective Strategy for Left-sided Obstructive Colon Cancer:A National, Propensity-score Matched Study

OBJECTIVE: The purpose of this population-based study was to compare decompressing stoma (DS) as bridge to surgery (BTS) with emergency resection (ER) for left-sided obstructive colon cancer (LSOCC) using propensity-score matching. SUMMARY BACKGROUND DATA: Recently, an increased use of DS as BTS for LSOCC has been observed in the Netherlands. Unfortunately, good quality comparative analyses with ER are scarce. METHODS: Patients diagnosed with nonlocally advanced LSOCC between 2009 and 2016 in 75 Dutch hospitals, who underwent DS or ER in the curative setting, were propensity-score matched in a 1:2 ratio. The primary outcome measure was 90-day mortality, and main secondary outcomes were 3-year overall survival and permanent stoma rate. RESULTS: Of 2048 eligible patients, 236 patients who underwent DS were matched with 472 patients undergoing ER. After DS, more laparoscopic resections were performed (56.8% vs 9.2%, P < 0.001) and more primary anastomoses were constructed (88.5% vs 40.7%, P < 0.001). DS resulted in significantly lower 90-day mortality compared to ER (1.7% vs 7.2%, P = 0.006), and this effect could be mainly attributed to the subgroup of patients over 70 years (3.5% vs 13.7%, P = 0.027). Patients treated with DS as BTS had better 3-year overall survival (79.4% vs 73.3%, hazard ratio 0.36, 95% confidence interval 0.20-0.65) and fewer permanent stomas (23.4% vs 42.4%, P < 0.001). CONCLUSIONS: In this nationwide propensity-score matched study, DS as a BTS for LSOCC was associated with lower 90-day mortality and better 3-year overall survival compared to ER, especially in patients over 70 years of age

Reduced respiratory motion artifacts using structural similarity in fast 2D dynamic contrast enhanced MRI of liver lesions

The purpose of this work was to improve dynamic contrast enhanced MRI (DCE-MRI) of liver lesions by removing motion corrupted images as identified by a structural similarity (SSIM) algorithm, and to assess the effect of this correction on the pharmacokinetic parameter Ktrans using automatically determined arterial input functions (AIFs). Fifteen patients with colorectal liver metastases were measured twice with a T1 weighted multislice 2D FLASH sequence for DCE-MRI (time resolution 1.2 s). AIFs were automatically derived from contrast inflow in the aorta of each patient. Thereafter, SSIM identified motion corrupted images of the liver were removed from the DCE dataset. From this corrected data set Ktrans and its reproducibility were determined. Using the SSIM algorithm a median fraction of 46% (range 37-50%) of the liver images in DCE time series was labeled as motion distorted. Rejection of these images resulted in a significantly lower median Ktrans (p < 0.05) and lower coefficient of repeatability of Ktrans in liver metastases compared with an analysis without correction. SSIM correction improves the reproducibility of the DCE-MRI parameter Ktrans in liver metastasis and reduces contamination of Ktrans values of lesions by that of surrounding normal liver tissu

Diffusion-weighted MR imaging in liver metastases of colorectal cancer: reproducibility and biological validation

Before diffusion-weighted imaging (DWI) can be implemented in standard clinical practice for response monitoring, data on reproducibility are needed to assess which differences outside the range of normal variation can be detected in an individual patient. In this study we assessed the reproducibility of the apparent diffusion coefficient (ADC) values in colorectal liver metastases. To provide a biological basis for these values, their relation with histopathology was assessed. DWI was performed twice in 1 week in patients scheduled for metastasectomy of colorectal liver metastases. Correlation between ADC values and apoptosis marker p53, anti-apoptotic protein BCL-2, proliferation marker Ki67 and serum vascular endothelial growth factor (VEGF) concentration were assessed. A good reproducibility coefficient of the mean ADC (coefficient of reproducibility 0.20 x 10(-3) mm(2)/s) was observed in colorectal liver metastases (n = 21). The ADC value was related to the proliferation index and BCL-2 expression of the metastases. Furthermore, in metastases recently treated with systemic therapy, the ADC was significantly higher (1.27 x 10(-3) mm(2)/s vs 1.05 x 10(-3) mm(2)/s, P = 0.02). The good reproducibility, correlation with histopathology and implied sensitivity for systemic treatment-induced anti-tumour effects suggest that DWI might be an excellent tool to monitor response in metastatic colorectal cance

Comparison of Decompressing Stoma vs Stent as a Bridge to Surgery for Left-Sided Obstructive Colon Cancer

Importance: Bridge to elective surgery using self-expandable metal stent (SEMS) placement is a debated alternative to emergency resection for patients with left-sided obstructive colon cancer because of oncologic concerns. A decompressing stoma (DS) might be a valid alternative, but relevant studies are scarce. Objective: To compare DS with SEMS as a bridge to surgery for nonlocally advanced left-sided obstructive colon cancer using propensity score matching. Design, Setting, and Participants: This national, population-based cohort study was performed at 75 of 77 hospitals in the Netherlands. A total of 4216 patients with left-sided obstructive colon cancer treated from January 1, 2009, to December 31, 2016, were identified from the Dutch Colorectal Audit and 3153 patients were studied. Additional procedural and intermediate-term outcome data were retrospectively collected from individual patient files, resulting in a median follow-up of 32 months (interquartile range, 15-57 months). Data were analyzed from April 7 to October 28, 2019. Exposures: Decompressing stoma vs SEMS as a bridge to surgery. Main Outcomes and Measures: Primary anastomosis rate, postresection presence of a stoma, complications, additional interventions, permanent stoma, locoregional recurrence, disease-free survival, and overall survival. Propensity score matching was performed according to age, sex, body mass index, American Society of Anesthesiologists score, prior abdominal surgery, tumor location, pN stage, cM stage, length of stenosis, and year of resection. Results: A total of 3153 of the eligible 4216 patients were included in the study (mean [SD] age, 69.7 [11.8] years; 1741 [55.2%] male); after exclusions, 443 patients underwent bridge to surgery (240 undergoing DS and 203 undergoing SEMS). Propensity score matching led to 2 groups of 121 patients each. Patients undergoing SEMS had more primary anastomoses (104 of 121 [86.0%] vs 90 of 120 [75.0%], P =.02), more postresection stomas (81 of 121 [66.9%] vs 34 of 117 [29.1%], P <.001), fewer major complications (7 of 121 [5.8%] vs 18 of 118 [15.3%], P =.02), and more subsequent interventions, including stoma reversal (65 of 113 [57.5%] vs 33 of 117 [28.2%], P <.001). After DS and SEMS, the 3-year locoregional recurrence rates were 11.7% for DS and 18.8% for SEMS (hazard ratio [HR], 0.62; 95% CI, 0.30-1.28; P =.20), the 3-year disease-free survival rates were 64.0% for DS and 56.9% for SEMS (HR, 0.90; 95% CI, 0.61-1.33; P =.60), and the 3-year overall survival rates were 78.0% for DS and 71.8% for SEMS (HR, 0.77; 95% CI, 0.48-1.22; P =.26). Conclusions and Relevance: The findings suggest that DS as bridge to resection of left-sided obstructive colon cancer is associated with advantages and disadvantages compared with SEMS, with similar intermediate-term oncologic outcomes. The existing equipoise indicates the need for a randomized clinical trial that compares the 2 bridging techniques.

Diffusion-weighted MR imaging in liver metastases of colorectal cancer: reproducibility and biological validation

Contains fulltext : 118299pub.pdf (publisher's version ) (Closed access)OBJECTIVES: Before diffusion-weighted imaging (DWI) can be implemented in standard clinical practice for response monitoring, data on reproducibility are needed to assess which differences outside the range of normal variation can be detected in an individual patient. In this study we assessed the reproducibility of the apparent diffusion coefficient (ADC) values in colorectal liver metastases. To provide a biological basis for these values, their relation with histopathology was assessed. METHODS: DWI was performed twice in 1 week in patients scheduled for metastasectomy of colorectal liver metastases. Correlation between ADC values and apoptosis marker p53, anti-apoptotic protein BCL-2, proliferation marker Ki67 and serum vascular endothelial growth factor (VEGF) concentration were assessed. RESULTS: A good reproducibility coefficient of the mean ADC (coefficient of reproducibility 0.20 x 10(-3) mm(2)/s) was observed in colorectal liver metastases (n = 21). The ADC value was related to the proliferation index and BCL-2 expression of the metastases. Furthermore, in metastases recently treated with systemic therapy, the ADC was significantly higher (1.27 x 10(-3) mm(2)/s vs 1.05 x 10(-3) mm(2)/s, P = 0.02). CONCLUSIONS: The good reproducibility, correlation with histopathology and implied sensitivity for systemic treatment-induced anti-tumour effects suggest that DWI might be an excellent tool to monitor response in metastatic colorectal cancer